The Collaborative International Dictionary
Sibilancy
Sibilance \Sib"i*lance\, Sibilancy \Sib"i*lan*cy\, n. The quality or state of being sibilant; sibilation.
Milton would not have avoided them for their sibilancy,
he who wrote . . . verses that hiss like Medusa's head
in wrath.
--Lowell.
Wiktionary
sibilancy
n. the state or property of being sibilant
Usage examples of "sibilancy".
From the device came a vicious whirring, much the same vibrant sibilancy as that of a rattlesnake about to strike.
The unheard metallic voice which yet gave the strong suggestion of sibilancy now sounded casual, almost friendly.